The present invention relates to a closure element of a slide closure for liquid melt containers, e.g., steel ladles, which closure element consists of a metallic support element having bearing surfaces, and a refractory plate embedded in such support element by means of refractory material and having a sliding surface and a passage opening, as well as to a process for manufacturing such a closure element.
The closure element is preferably employed as a stationary apertured plate or as a movable slide plate of a slide closure for vessels containing melts at high temperatures.
It is known that the reliable operation of such a slide closure depends largely on the clean and precise fitting of the refractory parts, i.e. of the stationary apertured plate and the movable slide plate, of the vessel. In such closures it is of extreme importance that the two plates which form the closure proper always rest or slide on each other with full sealing contact during the opening and closing operations. Devices for achieving such full sealing contact have already been proposed. However, such devices have not proven entirely satisfactory for the following reasons.
While the slide plate glides or slides on the stationary apertured plate, the support element which contains the side plate has bearing surfaces which ride on stationary guide ribs or ridges of the closure cover. Accordingly, care must be take that the bearing surfaces of the support element and the sliding surface of the slide plate always be plane parallel to each other within very low tolerances, preferably smaller than 1/100 mm, if jamming of the slide is to be avoided. It is hardly possible or economical to manufacture every coupling and fitting surface of slide plate and support element with a precision that corresponds to such tolerances. Accordingly, the irregularities of manufacture were compensated in known slide closures by the provision of a motor bed or layer between the plate and the support element. The compensation thereby achieved is generally effective when provided by very skilled technicians and while making use of known auxiliary devices.
A known auxiliary device of this type is described in German printed specification DT-AS No. 1,301,446 and in German specification DT-OS No. 2,031,938. However, such device exhibits two disadvantages, particularly in the case of large slide closures. The proper mounting of the plate in the support element of the closure element depends on the consistency of mortar. If the mortar is too hard, the forces required for the plane parallel forcing of the plate into the mortar bed are too high. If the mortar is too soft, the plate will change its position in the mortar bed in an unforeseen and generally irregular manner under the effect of its own weight, after the mounting operation and prior to the hardening of mortar, which change of position is unacceptable. Furthermore, the immovable mounting of the plate is completed only after the full setting of the mortar, which setting takes time.